Vinyl polymerization: 414. Polymerization of vinyl monomer initiated by poly(N,N,N-trimethyl-N-2-methacryloxyethyl)ammonium chloride

The polymerization of vinyl monomer initiated by an aqueous solution of poly(N,N,N-trimethyl-N-2-methacryloxyethyl)ammonium chloride (poly(Q-DMAEM-CI) has been carried out at 85°C. The effects of the amounts of vinyl monomer, poly(Q-DMAEM-CI) and water on the conversion of vinyl monomer have been studied. The overall activation energy in the polymerization of MMA is estimated as 41.9 kJ mol^?1. The polymerization proceeds through a radical mechanism. The location in which the polymerization occurs is discussed. The selectivity for vinyl monomer is explained by ‘the concept of hard and soft hydrophobic areas and monomers’.     

Decomposition rate control of PLLA plate by heat treatment

It is difficult to control the decomposition rate and the mechanical property of scaffolds after forming the poly(L ‐lactide) (PLLA) scaffolds. The purpose of this study is to control the decomposition rate and mechanical properties of the PLLA plate after forming. We carried out accelerated decomposition experiments using the enzyme on the (PLLA) with various crystallinity, which were prepared by changing the heat treatment condition, and elucidated the relationship between the crystallinity and the decomposition rate. A high positive correlation was observed between the heat treatment temperature and the crystallinity. A high negative correlation was observed between the crystallinity and the decomposition rate. Using the obtained empirical formula, it became possible to calculate the required period to decompose a certain amount of the PLLA if the heat treatment temperature was known. Changing the crystallinity of the PLLA plate could arbitrarily control the decomposition rate of the PLLA plate after forming. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

New Insights into Additive Structure Effect on Crystal Agglomeration of L‐Valine

Specific small amounts of amino acids caused agglomeration of L‐valine (L‐Val) crystals during evaporative crystallization from aqueous solutions. The agglomeration of L‐Val occurred only under acidic condition when guest amino acids satisfied several conditions. Only L‐form amino acids that have carboxylic acid groups and sufficiently long alkyl chain in the side‐chains could induce agglomeration of L‐Val. The length of alkyl chain in the side‐chains controls the degree of agglomeration. Data indicated only 0.5 wt % of L‐2‐aminoadipic acid, which has a similar chemical structure to L‐glutamic acid (L‐Glu), produced the large agglomerates > 1000 μm. The particle size was ～ 500 μm when using the same amount of L‐Glu. Based on the results from previous tests and this paper, the whole mechanism for the L‐Val agglomeration in the presence of specific guest amino acids has been revealed.     

Constrained sintering and cracking of air plasma sprayed thermal barrier coatings: Experimental observation and modeling

The development of vertical cracks in air plasma sprayed (APS) thermal barrier coatings (TBCs) during thermal cycling and constrained sintering under a temperature gradient is investigated. Microstructural analysis shows that the development of the vertical cracks is associated with multiple processes, including sintering during the hold period and cleavage during cooldown. Inspired by the experimental observations, an image-based sintering model is used to simulate the development of vertical cracks as the coating sinters while constrained by a substrate. The computational results show that microstructural imperfections can develop into vertical cracks, which then propagate toward the interface. A simple analytical model is presented for the threshold level of in-plane stress for the onset of propagation of a vertical crack during constrained sintering. By combining the results of these different modeling approaches, the cross-coupling of the material and geometric parameters, and how this determines the sintering response (microstructure evolution) and vertical crack formation is evaluated. In addition, the growth of vertical cracks by a cleavage mechanism during cooldown is examined and the coupling between sintering, cleavage crack growth, and TBC lifetime is explored.     

The molecular weight ratio of monomethoxypolyethylene glycol (mPEG) to protein determines the immunotolerogenicity of mPEG proteins

Immunotolerogenic activity of monomethoxypolyethylene glycol-(mPEG) conjugated proteins is a beneficial property in proteinpharmaceutics. However, procedures for the preparation of tolerogenicmPEG proteins have not yet been defined. We prepared mPEG proteinswith different mPEG contents using three proteins, hen egg lysozyme,ovalbumin and bovine gamma globulin, and their tolerogenicitiesto antigen-specific T and B cell responses were examined. Wefound the most appropriate ratio of tolerance induction to be1.5–2.0, which is the molecular weight ratio of conjugatedtotal mPEGs to protein. This value may assist in the preparationof tolerogenic mPEG proteins.     

Effect of trehalose accumulation on response to saline stress in Saccharomyces cerevisiae

To examine the effect of trehalose accumulation on response to saline stress in Saccharomyces cerevisiae, we constructed deletion strains of all combinations of the trehalase genes ATH1, NTH1 and NTH2 and examined their growth behaviour and intracellular trehalose accumulation under non‐stress and saline‐stress conditions. Saline stress was induced in yeast cells by NaCl addition at the exponential growth phase. All deletion strains showed similar specific growth rates and trehalose accumulation to their parent strain under non‐stress conditions. However, under the saline stress condition, one single deletion strain, nth1Δ, two double deletion strains, nth1Δ ath1Δ and nth1Δ nth2Δ, and the triple deletion strain nth1Δnth2Δ ath1Δ, all of which carry the nth1Δ deletion, showed increased trehalose accumulation as compared to the parent and other deletion strains. In particular, our statistical analysis revealed that the triple deletion strain showed a higher growth rate under the saline stress condition than the parent strain. Moreover, some deletion strains showed further trehalose accumulation under non‐stress conditions by overexpression of the TPS1 or TPS2 genes encoding the enzymes related to trehalose biosynthesis at the mid‐exponential phase. Such increased trehalose accumulation prior to NaCl addition could improve the growth of these strains under saline stress. Our results indicate that high trehalose accumulation prior to NaCl addition, rather than after NaCl addition, is necessary to achieve high growth activity under stress conditions. Copyright © 2009 John Wiley & Sons, Ltd.     

Faults and Claims about Thermal Environments in Relation to Energy Saving Measures in Smaller Office Buildings

Building equipment, energy-saving systems, and claims of inappropriate indoor thermal environments were analyzed in relation to the floor area using responses to a questionnaire survey of service managers of 157 buildings built in Osaka, Kyoto and Hyogo prefectures in Kinki area of Japan. Results show the following： （1） In smaller buildings （〈 5,000 m2）, setting temperatures are higher in summer and lower in winter, effects of ＂uncomfortable radiation from windows＂ are greater, energy-saving systems decrease indoor thermal comfort, but claims of ＂hot＂ and ＂cold＂ are fewer; （2） Claims of ＂hot＂ and ＂cold＂ are unrelated to the setting temperature and whether the air-conditioning control system is central or local; （3） The adoption rates of mitigation of dress codes （＂COOL-BIZ＂ and ＂WARM-BIZ＂） are higher than those of temperature mitigation of air conditioning.     

铁路复线施工的控制爆破

我国的爆破工程主要是根据实践经验计算的。施工经验公式不采用量纲分析法，许多经验系数取值范围较宽，失去了物理意义。而且这些公式的适用范围很窄，影响了爆破设计参数使用的精确性。根据Ｕ．ｌａｎｇｅｆｏｒｓ阐述的基本原理，结合我国的实际经验，提出了一套炮孔爆破的设计和计算方法，可供现场使用。